nekto

public function prepareListObject(xPDOObject $object) {
        $data = array();
        $data['id'] = $object->id;
        $data['pagetitle'] = $object->pagetitle;
        $data['content'] = $object->content;
        return $data;
    }

$c->select('id');

<?php

class ResourceControllerResource extends modRestController {
    
    public $classKey = 'modResource';
    public $defaultSortField = 'id';
    public $defaultSortDirection = 'ASC';
    
    
    public function prepareListQueryBeforeCount(xPDOQuery $c) {
        
      
    $c->select($this->modx->getSelectColumns('site_content','site_content','zx_', array('id','pagetitle')));
      
    
    return $c;
}


return 'ResourceControllerResource';